A hammerless, striker fired model 1911 handgun and associated methods is disclosed in U.S. Pat. No. 8,720,096, the disclosure of which is incorporated herein by reference. This disclosure relates to an improved firing system for such a hand gun. In particular, the firing system is a striker fired mechanism that replaces the pivoting hammer system that actuates the firing pin and uses the remaining components of the handgun. The system may utilize other existing components found on pivoting hammer actuating-type firearms. For instance, as described below in further detail, the sear assembly may be installed in a conventional pivoting hammer actuated-type system and cooperate with an existing trigger mechanism to allow its use. The handgun may be constructed with the disclosed hammerless, striker fired system. In the alternative, the handgun may be retrofitted with the disclosed hammerless, striker fired system replacing the pivoting hammer that ordinarily actuates the firing pin. Such an assembly is shown in co-owned application Ser. No. 29/499,396, the disclosure of which is incorporated herein. Accordingly, this disclosure incorporates methods of modifying existing handguns to incorporate a hammerless, striker fired system.